"Anti-time: as intractable and destructive a force to causality as antimatter is to space. Something with no past, no present, no future. A perpetuity of meaningless chaos. A Now, with no beginning or end. Elegant, brilliant, thoroughly logical... and utter gibberish." (AUDIO: Neverland)

Time Lord theories suggested that anti-time was created when Rassilon created the Eye of Harmony, binding the universe to a single continuity.

The Neverpeople attempted to destroy Gallifrey using a bomb filled with anti-time. The Time Lords on the ship were infected by anti-time, and set the Time Station to explode. However, the Eighth Doctor saved Gallifrey by materialising his TARDIS around the Time Station, thus containing the anti-time explosion. The Doctor and his TARDIS absorbed the anti-time energy released. Both were "infected" by it, and took on the persona of Zagreus. (AUDIO: Neverland)

Zagreus was courted by Rassilon to become his assassin. The TARDIS' outer shell was melted down in Rassilon's Foundry, and Zagreus formed a blade of anti-time, with which Rassilon hoped the Doctor would cut the Divergence from time. With the help of Charley and the TARDIS' "good side", the Doctor managed to reassert his personality long enough to refuse the offer and hurl Rassilon into the Divergent Universe. The infection was stabilised with pure zero matter. The Doctor, however, was forced to travel into a Divergent Universe to keep the Anti-Time and the Zagreus personality under control. (AUDIO: Zagreus)

The anti-time was eventually purged from the Doctor's system by Rassilon. (AUDIO: The Next Life)